A method of this type and a device of this type are known, for example, from document U.S. Pat. No. 5,832,712.
During the increasing discussion of possible climate changes caused by the increase of the carbon dioxide concentration in the Earth's atmosphere (“greenhouse effect”), which is attributable primarily to the burning of fossil fuels, such as natural gas, mineral oil and coal, there is an increasing range of proposals being put forward as to how, for example in fossil-fired power plants, the carbon dioxide can be removed from the flue gases of the boiler or exhaust gases from gas turbine plants on an industrial scale before it is released into the atmosphere.
One of these proposals is described in U.S. Pat. No. 5,344,627. In this proposal, the flue gas from the fossil-fired boiler of a steam power plant is brought into contact, in countercurrent, with a liquid which absorbs carbon dioxide and contains, for example, an alkanolamine. The carbon dioxide which is absorbed by the liquid is removed from the liquid again at a different point in the liquid cycle and is then liquefied. The liquid cycle together with the necessary absorption and regeneration columns requires a substantial outlay on plant engineering.
Another proposal, which is known from U.S. Pat. No. 5,665,319, for removing carbon dioxide from a gas which contains carbon dioxide uses, instead of a liquid, a granular metal oxide, which is converted into a metal carbonate by absorbing carbon dioxide and is converted back into the metal oxide by subsequent removal of the carbon dioxide. The granular powder is either conveyed back and forth in a cycle between a fixation tower and a decomposition furnace, or two similar devices with a solid powder bed are used alternately to absorb and release the carbon dioxide by switching between the devices. A drawback of this method is that the device in which the carbon dioxide is released again must in each case be operated as an externally heated furnace.
Finally, in the document U.S. Pat. No. 5,832,712 which is mentioned in the introduction, it is proposed to remove the carbon dioxide from the exhaust gas from a gas turbine plant by bringing the exhaust gas, after it has passed through a heat recovery steam generator, into contact with a liquid which absorbs carbon dioxide in an absorption column. In this case too, there is the drawback of the outlay on plant engineering for the liquid cycle of the absorbing liquid.